Post-Manufacture Glass Container Thermal Strengthening on a Conveyor

ABSTRACT

A method of manufacturing of strengthened glass containers, and more particularly a method of thermally strengthening glass containers in a glass container manufacturing line while they are on a conveyor intermediate the hot end and the cold end. Glass containers formed at an I. S. machine are conveyed through a special tempering Lehr that heats them uniformly to a high temperature that is short of temperatures at which they may become deformed. Subsequently, the glass containers while being transported on a conveyor are subjected to a unique rapid thermal strengthening cooling process in which the outer and inner surfaces including all areas of the glass containers are simultaneously cooled to a temperature below the Strain Point of the glass used in the glass containers.

IDENTIFICATION OF RELATED PATENT APPLICATIONS

This patent application claims priority of U.S. Provisional PatentApplication No. 61/328,043, which is entitled “Post-Manufacture GlassContainer Thermal Strengthening Method,” and which was filed on May 25,2010, which patent application is hereby incorporated herein byreference in its entirety.

This application is related to seven other concurrently filed copendingpatent applications, namely U.S. patent application Ser. No. ______,entitled “Post-Manufacture Glass Container Thermal StrengtheningMethod;” U.S. patent application Ser. No. ______, entitled“Post-Manufacture Glass Container Thermal Strengthening Station;” U.S.patent application Ser. No. ______, entitled “Cooling Tube MechanismOperation in a Post-Manufacture Glass Container Thermal StrengtheningStation;” U.S. patent application Ser. No. ______, entitled “CoolingTube Nozzle for a Post-Manufacture Glass Container Thermal StrengtheningStation;” U.S. patent application Ser. No. ______, entitled “CoolingShroud for a Post-Manufacture Glass Container Thermal StrengtheningStation;” U.S. patent application Ser. No. ______, entitled “BaseCooling Nozzle for a Post-Manufacture Glass Container ThermalStrengthening Station;” and U.S. patent application Ser. No. ______,entitled “Bottom Cooler for a Post-Manufacture Glass Container ThermalStrengthening Station,” all of which are assigned to the assignee of thepresent patent application, which seven patent applications are eachhereby incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates generally to the manufacture ofstrengthened glass containers, and more particularly to a method ofthermally strengthening glass containers in a glass containermanufacturing line while they are on a conveyor intermediate the hot endand the cold end.

There are two broad categories of glass that are used in glasscontainers such as bottles, namely “hard” glass and “soft” glass. “Hard”glass, also called borosilicate glass, is made of silica and boronoxide, requires much higher temperatures and is more difficult to form,and costs more than soft glass to manufacture, although it has excellentthermal stress characteristics. “Soft” glass, or soda-lime orsoda-lime-silicate glass, is made of soda, lime, silica, alumina, andsmall quantities of fining agents, and may be manufactured at lowertemperatures and is easier to form and cheaper to manufacture, althoughits thermal stress characteristics are not as good as hard glass. “Soft”glass is the more prevalent type of glass, and it is commonly used forglass containers. For cost reasons, glass containers today are primarilymade of soda-lime glass by molding molten glass into glass containers inblow molds.

Glass containers are made in a manufacturing process that has threeparts, namely the batch house, the hot end, and the cold end. The batchhouse is where the raw materials for glass (typically including sand,soda ash, limestone, cullet (crushed, recycled glass), and other rawmaterials) are prepared and mixed into batches. The hot end begins witha furnace, in which the batched materials are melted into molten glass,and from which a stream of molten glass flows.

The molten glass is cut into cylinders of glass called gobs, which fallby gravity into blank molds. In the blank molds, a pre-containerreferred to as a parison is formed, either by using a metal plunger topush the glass into the blank mold, or by blowing the glass from belowinto the blank mold. The parison is inverted and transferred to a mold,where the parison is blown out into the shape of the container. The hotend also includes an annealing process which prevents the containersfrom having weakened glass caused by stresses due to uneven cooling. Theannealing process is used to achieve even cooling, using an annealingoven or Lehr to heat the containers, and then slowly cool them over atwenty to sixty minute period. This annealing process is described, forexample, in U.S. Pat. No. 3,463,465, to Fuller, which patent is assignedto the assignee of the present patent application and is herebyincorporated herein by reference. Such a glassware annealing Lehrtypically has a plurality of tunnel defining modules connected to oneanother in an end-toward-end relationship, with an endless conveyorhaving an upper run extending through the tunnel. Each of the moduleshas an air circulating chamber below the conveyor upper run, a topportion defining a plenum chamber with an inlet and outlet slots, andair moving means drawing air through the inlet opening and dischargingthe at a high velocity out of the outlet slots through said conveyorupper run into the circulating chamber.

The equipment at the cold end of the glass container manufacturingprocess inspects the containers to ensure that they are of acceptablequality. All glass containers are inspected by automated machines aftermanufacturing for a variety of faults, typically including small cracksin the glass referred to as checks, foreign inclusions referred to asstones, bubbles in the glass referred to as blisters, and excessivelythin walls. Sample glass containers are also typically subjected todestructive testing to verify such characteristics as the strength andthe hardness of the glass containers.

The assignee of the present patent application developed a process tothermally strengthen these glass containers at the hot end, in partwhile they are still within the blow molds. Instead of relying solelyupon annealing the glass containers in the Lehr to remove stress, boththe outside walls and the inside walls of the glass containers arecooled at the hot end within the blow molds prior to transfer to theLehr to produce heat strengthened soda lime glass containers which haveintentionally introduced stress profiles across the walls of the glasscontainer.

This process initially occurs within the blow molds, with the blow headsbeing moved slightly away from the finish of the blown glass containersand the blow tubes being oscillated up and down within the glasscontainers to cool their interiors while simultaneously blowing coolingair through passages within the blow molds to cool the exteriors of theglass containers. The formed glass containers are then transferred fromthe forming stations to deadplate cooling locations at which coolingshrouds or “cans” surround the exteriors of the glass containers andutilize cooling air passing therethrough to cool the external surfacesof the glass containers while oscillating cooling tubes extending intothe interiors of the glass containers are used to cool the internalsurfaces of the glass containers.

This cooling process causes compressive stresses on both the insidewalls and the outside walls of the glass container, and tensional stressin the interior of the walls of the glass container. The thermal energyof the glass containers is thereby reduced to a point where the glasscontainers are fully tempered before being deposited on a conveyor, andfurther cooling can accordingly take place at a rapid rate withoutcausing defects in the glass containers. Subsequent conveyor cooling maybe performed within a cooling tunnel prior to supplying the partiallycooled glass containers to a conventional Lehr.

Thermally strengthened soda lime glass containers that are producedthrough the use of the improved cooling technology referenced above aresubstantially stronger and more durable, and are much less likely tobreak when subjected to mechanical loading or handling or a suddentemperature change. The improvements discussed briefly above aredescribed in greater detail in U.S. Pat. No. 6,705,121, to Mungovan etal., in U.S. Pat. No. 6,766,664, to Hyre et al., in U.S. Pat. No.6,766,665, to Hyre et al., in U.S. Pat. No. 6,776,0009, to Hyre et al.,in U.S. Pat. No. 6,766,010, to Fenton, in U.S. Pat. No. 6,782,719, toFenton, in U.S. Pat. No. 6,807,826, to Fenton, in U.S. Pat. No.6,807,827, to Anheyer et al., in U.S. Pat. No. 6,807,829, to Fenton etal., in U.S. Pat. No. 6,810,690, to Fenton et al., in U.S. Pat. No.6,813,905, to Fenton, in U.S. Pat. No. 6,823,696, to Fenton et al., inU.S. Pat. No. 6,854,292, to Pinkerton, in U.S. Pat. No. 6,857,291, toDiehm et al., in U.S. Pat. No. 6,857,292, to Fenton, in U.S. Pat. No.6,865,910, to Fenton, in U.S. Pat. No. 7,487,650, to Hyre et al., and inU.S. patent application Ser. No. 11/890,056, to Hyre et al., whichpatents and patent application are all assigned to the assignee of thepresent patent application and are all hereby incorporated herein byreference.

There is a continuing focus on the reduction of costs in the bottlingindustries, and this focus includes a strong desire for a reduction inthe weight of glass containers. A reduction in the weight of glasscontainers decreases the cost in raw materials required to make them aswell as the energy required to heat the glass (and the amount of heatthat must be removed from formed glass containers). Lighter weight glasscontainers can also result in a reduction of the cost of transportation,and when emptied there is less material to either recycle or otherwisedispose of.

While glass in its pristine state is extremely strong, stressconcentrations are introduced during the forming process. While theshape of glass containers can be optimized to remove unwanted stressincreasing geometry, it is inevitable that lighter weight glasscontainers will have thinner walls. When lighter weight glass containersare manufactured using known glass container manufacturing processes, itis inevitable that, with all other factors being equal, lighter weightglass containers are less strong than heavier (thicker walled) glasscontainers.

It is accordingly desirable that the present invention provide animproved glass container manufacturing process that results in anincrease in the strength of the glass containers manufactured accordingto the improved process. It is also desirable that this increase in thestrength of glass containers be obtainable for glass containers of anydesign geometry. It is further desirable that the improved glasscontainer manufacturing process make it possible to make lighter weightglass containers that have at least the same strength as conventionalnon-light weight glass containers.

It is further desirable that the improved glass container manufacturingprocess be adaptable to existing glass container manufacturing lines.Further, it is desirable that the improved glass container manufacturingprocess not require either a replacement or a reconfiguration ofexisting I.S. machines at the hot end of glass container manufacturinglines. It is also desirable that the improved glass containermanufacturing process be accomplished without requiring the use ofchemical strengthening methods to alter the hardness characteristics ofthe glass containers.

The apparatus used in the improved glass container manufacturing processmust be of construction which is both durable and long lasting, and itshould also require little or no maintenance to be provided by the userthroughout its operating lifetime. In order to enhance the market appealof this apparatus, it should also provide sufficient advantage in themanufacture of glass containers over conventional glass containermanufacture to thereby afford it the broadest possible market. Finally,it is also an objective that all of the aforesaid advantages be achievedwithout incurring any substantial relative disadvantage.

SUMMARY OF THE INVENTION

The disadvantages and limitations of the background art discussed aboveare overcome by the present invention. With this invention, apost-manufacture glass container thermal strengthening process isperformed after glass containers are formed at the hot end of a glassmanufacturing line while they are on a conveyor (the hot end includes I.S. machines that form the glass containers from gobs of molten glass)and before the cold end of the glass manufacturing line, where completeglass containers are optionally coated and are then inspected. Thepost-manufacture glass container thermal strengthening process practicedby the present invention takes the place of a conventional annealingoperation in a Lehr, where glass containers are gradually cooled in aconventional annealing process.

Glass containers formed in an I. S. machine that are at temperatures of500 degrees Centigrade to 600 degrees Centigrade are conveyed through aspecial tempering Lehr that heats them uniformly to a temperature ofbetween approximately 620 degrees Centigrade and approximately 660degrees Centigrade as they exit the special tempering Lehr. The specialtempering Lehr is similar in construction to an annealing Lehr, exceptthat it heats the glass containers up as they pass therethrough. Theymust be at least approximately 620 degrees Centigrade in order to obtainadequate compressive stresses, and not hotter than approximately 660degrees Centigrade since at hotter temperatures they may becomedeformed.

Following heating the glass containers to the desired temperature range,they are subjected to a unique rapid thermal strengthening coolingprocess in which the outer and inner surfaces including all areas of theglass containers are simultaneously cooled to a temperature below theStrain Point of the glass used in the glass containers. Preferably, theglass containers are cooled in this rapid thermal strengthening coolingprocess to a temperature range of between approximately 400 degreesCentigrade and approximately 450 degrees Centigrade.

In the preferred embodiment, the rapid thermal strengthening coolingprocess is accomplished by placing each of the glass containers in acylindrical cooling shroud that is open on both the top and the bottomthereof. The cooling shroud has a large plurality of tiny apertureslocated therein through which cooling air is blown to cool the outersurfaces of a glass container located within the cooling shroud.Optionally, the cooling shroud may be rotated and/or oscillated to“smear” the jets of cooling air directed on the outer surfaces of theglass container. A nozzle located in each of the cooling shrouds nearthe bottom thereof blows cooling air upwardly to cool the bottom of aglass container located within the cooling shroud. Alternatively, anannular bottom cooler blowing cooling air from a circular gap close tothe walls in each cooling shroud that is open below the glass containermay be used instead of the cooling nozzle. A cooling tube having anozzle on the bottom thereof is lowered into the glass container and maybe oscillated up and down to cool the inner surfaces of a glasscontainer located within the cooling shroud. All of these coolingoperations occur simultaneously, with the temperature of the entireglass container thusly being rapidly lowered.

The glass containers are then removed from the cooling shrouds, and maythen be placed on a conveyer under or adjacent arrays or banks of fansand further cooled as desired prior to entering the cold end of themanufacturing line. Alternately, additional segments of Lehrs may beused to further cool the glass containers.

In an alternate embodiment, the glass containers are thermallystrengthened in a glass container manufacturing line while they are on aconveyor intermediate the hot end and the cold end. In anotheralternative embodiment, finished annealed glass containers that havebeen through the entire manufacturing process and are cold may bereheated in a special tempering Lehr to a high temperature and then havethe post-manufacture glass container thermal strengthening processpracticed by the present invention performed upon them. This may be analternative when an existing glass container manufacturing line is notto be modified for business reasons.

It may therefore be seen that the present invention teaches apost-manufacture glass container thermal strengthening process performedwhile the glass containers are on a conveyor that results in an increasein the strength of the glass containers manufactured according to theimproved process. This increase in the strength of glass containers isobtainable by the post-manufacture glass container thermal strengtheningprocess practiced by the present invention for glass containers of anydesign geometry. The post-manufacture glass container thermalstrengthening process enables the manufacture of lighter weight glasscontainers that have at least the same strength as conventionalnon-light weight glass containers.

The post-manufacture glass container thermal strengthening processpracticed by the present invention is fully adaptable to most if not allexisting glass container manufacturing lines. Further, thepost-manufacture glass container thermal strengthening process does notrequire either a replacement or a reconfiguration of existing I.S.machines at the hot end of glass container manufacturing lines. Thepost-manufacture glass container thermal strengthening processstrengthens glass containers without requiring the use of chemicalstrengthening methods to alter their hardness characteristics.

The apparatus used in the post-manufacture glass container thermalstrengthening process practiced by the present invention is of aconstruction which is both durable and long lasting, and which willrequire little or no maintenance to be provided by the user throughoutits operating lifetime. The advantages provided by the post-manufactureglass container thermal strengthening process practiced by the presentinvention substantially enhance its market appeal and thereby afford itthe broadest possible market. Finally, all of the aforesaid advantagesand objectives of the post-manufacture glass container thermalstrengthening process practiced by the present invention are achievedwithout incurring any substantial relative disadvantage.

DESCRIPTION OF THE DRAWINGS

These and other advantages of the present invention are best understoodwith reference to the drawings, in which:

FIG. 1 is a curve representing an optimal stress parabola plottedagainst the thickness of a side wall of a glass container;

FIG. 2 is a curve representing viscosity plotted against temperature;

FIG. 3 is flow diagram depicting the post-manufacture glass containerthermal strengthening process practiced by the present invention;

FIG. 4 is a schematic cross-sectional view showing a reheated glasscontainer about to have the post-manufacture glass container thermalstrengthening method performed upon it, with a cylindrical coolingshroud and a base cooling nozzle located below the glass container and acooling tube having a nozzle at its bottom end being located above theglass container;

FIGS. 5 and 6 are schematic diagrams showing the glass container shownin FIG. 4 disposed inside the cylindrical cooling shroud and above thebase cooling nozzle located in the cooling shroud, with the cooling tubehaving the nozzle at its bottom end being located inside the glasscontainer to perform the post-manufacture glass container thermalstrengthening method;

FIG. 7 is an isometric view of the cooling shroud illustrated in FIGS. 5and 6 from the top and side thereof;

FIG. 8 is a side plan view of the cooling shroud illustrated in FIGS. 5through 7;

FIG. 9 is a top end view of the cooling shroud illustrated in FIGS. 5through 8;

FIG. 10 is a first cross-sectional view of the cooling shroudillustrated in FIGS. 5 through 9;

FIG. 11 is a second cross-sectional view of the cooling shroudillustrated in FIGS. 5 through 10;

FIG. 12 is an enlarged view of a portion of the cooling shroudillustrated in FIG. 10;

FIG. 13 is an isometric view of the tube cooling nozzle illustrated inFIGS. 5 and 6 from the top and side thereof;

FIG. 14 is a top end view of the tube cooling nozzle illustrated inFIGS. 5, 6, and 13;

FIG. 15 is a cross-sectional view of the tube cooling nozzle illustratedin FIGS. 5, 6, 13, and 14;

FIG. 16 is an isometric view of the base cooling nozzle illustrated inFIGS. 5 and 6 from the top and side thereof;

FIG. 17 is a top end view of the base cooling nozzle illustrated inFIGS. 5, 6, and 16;

FIG. 18 is a cross-sectional view of the base cooling nozzle illustratedin FIGS. 5, 6, 16, and 17;

FIG. 19 is an exploded isometric view of a post-manufacture glasscontainer thermal strengthening apparatus for performing the coolingportion of the post-manufacture glass container thermal strengtheningprocess;

FIG. 20 is a side plan view of the post-manufacture glass containerthermal strengthening apparatus illustrated in FIG. 19, also showing thedistal end of a supply conveyor for providing reheated glass containersto the post-manufacture glass container thermal strengthening apparatus,as well as the proximal end of a discharge conveyor for conveyingthermally strengthened glass containers discharged by thepost-manufacture glass container thermal strengthening apparatus;

FIGS. 21 through 28 are cross-sectional side views of portions of thepost-manufacture glass container thermal strengthening apparatus and theends of the supply and discharge conveyors showing the sequence ofoperations as a reheated glass container has the post-manufacture glasscontainer thermal strengthening method used to thermally strengthen it;

FIG. 29 is an isometric view of the takeout tongs operating assembly ofthe post-manufacture glass container thermal strengthening apparatusshown in FIG. 19;

FIG. 30 is a plan view of the cooling tube operating assembly of thepost-manufacture glass container thermal strengthening apparatus shownin FIG. 19;

FIG. 31 is a an isometric view of two cooling shroud mechanisms of thecooling portion of the post-manufacture glass container thermalstrengthening process practiced by the present invention illustrated inFIGS. 19 and 20, each of which cooling shroud mechanisms is for coolingtwo containers, showing one of the cooling shroud mechanisms raised andthe other of the cooling shroud mechanisms lowered;

FIGS. 32 through 35 are partially cutaway cross-sectional views of thecooling shroud mechanisms illustrated in FIG. 31, showing thetelescoping mechanisms providing cooling air to the cooling shrouds andthe base cooling nozzles;

FIG. 36 is an isometric view showing a special tempering Lehr having asupply conveyer extending therethrough to deliver reheated glasscontainers to the cooling tube operating assembly shown in FIGS. 19 and20;

FIG. 37 is an isometric view showing the cooling tube operating assemblyand a deadplate, an exit conveyor, and a pusher mechanism and a portionof the special tempering Lehr from a side opposite the side shown inFIG. 36;

FIG. 38 is a top plan view showing the cooling tube operating assemblyand a portion of the special tempering Lehr shown in FIG. 36;

FIG. 39 is an isometric view of an alternate embodiment bottom coolerfor mounting in the bottom of the cooling shroud illustrated in FIGS. 5through 11 from the top and side thereof;

FIG. 40 is a top end view of the alternate embodiment bottom coolerillustrated in FIG. 39;

FIG. 41 is a cross-sectional view of the alternate embodiment bottomcooler illustrated in FIGS. 39 and 40;

FIG. 42 is a cross-sectional view of the alternate embodiment bottomcooler illustrated in FIGS. 39 through 41 in the bottom of the coolingshroud illustrated in FIGS. 5 through 12;

FIG. 43 is a schematic cross-sectional depiction of an alternateembodiment post-manufacture glass container thermal strengtheningapparatus and method, showing cooling shrouds and cooling tubes mountedabove some glass containers on an air permeable conveyor andschematically depicted bottom cooling apparatus located below the glasscontainers below the cooling shrouds and cooling tubes; and

FIG. 44 is a schematic cross-sectional depiction of the alternateembodiment post-manufacture glass container thermal strengtheningapparatus and method illustrated in FIG. 43, showing the cooling shroudsand cooling tubes lowered over some glass containers on the airpermeable conveyor and the cooling apparatus located below the glasscontainers below the cooling shrouds and cooling tubes cooling the glasscontainers.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Prior to discussing exemplary embodiments of the post-manufacture glasscontainer thermal strengthening or hardening method practiced by thepresent invention, a brief discussion of some of the principles used bythe present invention will be provided. Thermal strengthening of a glasscontainer rapidly cools the inner and outer surfaces of the glasscontainer until the inner and outer surface temperatures are below theglass transition temperature, thereby “freezing” the surface structureof the glass container while allowing the inner glass to continue toflow until its temperature reaches the glass transition temperature,then letting the glass container cool to room temperature. When theglass container reaches room temperature, the inner and outer surfacesof the glass container will be in compression and the interior of thewalls of the glass container will be in tension. In a properlycontrolled cooling process, the stress along the thickness of the wallsof the glass container should thus vary from compression at the outerwalls to tension in the interior of the walls to compression at theinner walls, with very little or no net radial stress.

FIG. 1 illustrates a stress parabola that represents the idealtheoretical stress distribution throughout its wall varying fromcompression at the outer wall of a glass container to tension in theinterior of the wall of the glass container (including the midpoint ofthe wall) to compression at the inside wall of the glass container. Thestress profile through the glass is ideally parabolic in shape, havingthe area under the horizontal axis equal to the area above thehorizontal axis, wherein the sum of surface compression is balanced bysandwiched tension to result in a net stress of zero. Ideally, thesurface compression zone thickness is typically 21% of the total glasswall thickness on each side, therefore 42% is in compression and 58% intension. The maximum tension level is typically half of the surfacecompression stress.

The compression stress levels that are imparted on both inside andoutside surfaces of glass containers usually range between −20 MPa and−60 MPa. Industry standard levels for Annealed glass are 0 MPa (±5 MPa),for Heat Strengthened glass are −24 MPa to −52 MPa, for Tempered glassare −69 MPa to −103 MPa, and for Safety Glass are −103 MPa to −152 MPa.The post-manufacture glass container thermal strengthening processpracticed by the present invention is capable of producing glasscontainers having an outside compressive stress of 20 to 60 MPa whichresults in a buried tensile stress of 10 to 30 MPa.

In order to achieve a balanced stress profile having such compressivestress levels on the inner and outer surfaces of a glass container, itis necessary to cool both surfaces uniformly. Thin sections are the mostdifficult to temper due to the difficulty of obtaining a largetemperature differential between the inner and outer surfaces and thecore. Thin sections require higher heat transfer coefficients than dothicker areas.

FIG. 2 depicts an exemplary viscosity to temperature curve thatillustrates several key temperature-dependent characteristics of atypical glass container having the depicted viscosity to temperaturecurve. After the glass container is fully blown and has been removedfrom its mold, it must remain cooler than its Softening Point 60, whichis typically approximately 748 degrees Centigrade. The glass material ofthe glass container is a viscous liquid at temperatures above theSoftening Point 60, as illustrated by a viscous liquid rangecharacterization 62. Following the molding process, the glass containersare annealed in a conventional Lehr by gradually cooling them across aGlass Transition range 64 which is located in a wider Glass Viscoelasticrange 66 in which the glass of the glass container exhibits viscoelasticcharacteristics. The Glass Transition range 64 is the range oftemperatures in which the glass in the glass containers goes from beinga super-cooled liquid to being a solid.

An Annealing Point 68 is shown in the Glass Transition range 64, andthis Annealing Point 68 represents the temperature at which stresses inthe glass container will be relieved in a selected predefined timeperiod, typically a few minutes. For a typical glass container, theAnnealing Point 68 temperature may typically be approximately 555degrees Centigrade. At a temperature below approximately 550 degreesCentigrade, it would take hours instead of minutes to relieve thestresses in the glass container. At temperatures in the Glass Transitionrange 64 that are higher than the selected Annealing Point 68, it wouldtake less time to relieve the stresses in the glass container. Thestresses in the glass containers are locked in by cooling them to atemperature below the Strain Point 70, which is typically approximately532 degrees Centigrade, although it can vary to as low as approximately480 degrees Centigrade, depending upon particular glass formula used tomake the glass containers. It should be noted that these temperaturesmust be adhered to for even the thickest areas on the glass containers,which typically cool slower than the thinner areas of the glasscontainers.

Referring next to FIG. 3, the post-manufacture glass container thermalstrengthening process practiced by the present invention is illustratedin a flow diagram showing a thermal strengthening process 75 locatedintermediate a hot end process 76 and a cold end process 77. The processbegins at a melt glass materials step 78 in which the materials used tomake the molten glass are melted together in a furnace. The molten glassis supplied to the hot end process 76, beginning with the molten glassbeing distributed to blank or parison molds of an I.S. machine in adistribute gobs to blank molds step 79. Parisons are formed in theparison molds in a form parisons in blank molds step 80.

The parisons are placed within blow molds and blown in a place parisonsin blow molds and blow glass containers step 81. The blown glasscontainers are initially cooled below the Softening Point in the moldsin a cool glass containers in blow molds step 82, which ends theoperations of the hot end process 76. The hot glass containers are thenmoved to the Lehr conveyer in a move glass containers to Lehr conveyerstep 83, where in a conventional process they would begin the controlledheating and cooling that constitutes the conventional annealing glasscontainer annealing process. As depicted in FIG. 3, however, the hotglass containers are instead subjected to the thermal strengtheningprocess 75 practiced by the present invention.

The hot glass containers (they are typically 500 degrees Centigrade to600 degrees Centigrade at this point) entering the thermal strengtheningprocess are initially subjected to a reheat glass containers to highertemperature in a special tempering Lehr step 84. The special temperingLehr is hotter than a conventional Lehr, and may be, for example, set atapproximately 600 degrees Centigrade at its entrance and approximately715 degrees Centigrade at its exit. In the example presented herein, thespecial tempering Lehr may have a length of sixteen feet (4.9 meters)and may have four independent temperature controlled zones.

The typical time spent by the glass containers in the special temperingLehr is approximately two and one-half minutes to three and one-halfminutes, and the glass containers will be heated to a temperature ofbetween approximately 620 degrees Centigrade and approximately 680degrees Centigrade (but always to a temperature that is less than theSoftening Point). This temperature range is selected because if theglass containers are less than approximately 620 degrees Centigradeadequate compressive stresses cannot be obtained, and if the glasscontainers are over approximately 680 degrees Centigrade they may becomedeformed.

Following the reheat glass containers to higher temperature in a specialtempering Lehr step 84, the reheated glass containers are subjected to athermal strengthening cooling process 85, in which the glass containersare cooled to a temperature below the Strain Point, preferably to arange of between approximately 400 degrees Centigrade and approximately450 degrees Centigrade. In the thermal strengthening cooling process 85it is necessary that all areas of the glass containers are cooled belowthe Strain Point, including the thicker areas that typically take longerto cool. This cooling will be discussed in more detail below inconjunction with the discussion of the steps contained in the thermalstrengthening cooling process 85.

Following the thermal strengthening cooling step 85, the thermalstrengthening process 75 finishes in a glass containers further coolingstep 86 in which the temperature of the glass containers is reduced to atemperature of approximately 100 degrees Centigrade to approximately 150degrees Centigrade. The glass containers further cooling step 86 may beaccomplished by the use of fan arrays located over a conveyertransporting the thermally strengthened glass containers as they movefrom the thermal strengthening process 75 to the cold end process 77.

Alternately, if the post-manufacture glass container thermalstrengthening process is integrated into an existing glass containerproduction line in which the first section of the Lehr is used toperform the reheat glass containers to higher temperature in a specialtempering Lehr step 84, the remaining sections of the Lehr may be usedto cool the glass containers in the glass containers further coolingstep 86.

Another alternative would be to use the thermal strengthening process 75as an operation wholly separate from the glass container manufacturingoperation in which finished, fully cooled glass containers would bereheated in the reheat glass containers to higher temperature in aspecial tempering Lehr step 84, strengthened in the thermalstrengthening cooling step 85, and then cooled in the glass containersfurther cooling step 86.

Returning to the thermal strengthening cooling process 85, a preferredembodiment of this process is shown in the steps illustrated in FIG. 3.The glass containers coming from the special tempering Lehr in thereheat glass containers to higher temperature in a special temperingLehr step 84 are picked up from the conveyer belt exiting the specialtempering Lehr with tongs and are lifted to a position above coolingshrouds in a glass containers picked up and lifted above cooling shroudsstep 87. Next, cooling shrouds having cooling nozzles are raised tosurround the glass containers in a cooling shrouds with cooling nozzlesraised around glass containers step 88, and cooling tubes are loweredinto the interiors of the glass containers in a cooling tubes loweredinto glass containers step 89.

Cooling air is then supplied to the cooling shrouds, the coolingnozzles, and the cooling tubes in a cooling air supplied to coolingshrouds, cooling nozzles, and cooling tubes step 90, while the coolingshrouds are optionally rotated and the cooling tubes are oscillated in acooling shrouds rotated and cooling tubes oscillated step 91 tosimultaneously cool the exterior surfaces and the interior surfaces ofthe glass containers. It may be noted that the outside surfaces of theglass container finishes are conductively cooled with tong inserts inthe tongs supporting the glass containers throughout the thermalstrengthening cooling step 85. The glass containers are cooled to atemperature below the Strain Point in a glass container interior andexterior surfaces temperature simultaneously lowered step 92, preferablyto the range of between approximately 400 degrees Centigrade andapproximately 450 degrees Centigrade. Cooling times should be relativelyfast in order to allow the process to be used in commercialmanufacturing operations, and thus should be less than approximatelyfifteen to approximately twenty seconds for typical glass containers.Typical cooling times have been found to range from approximately nineseconds to approximately twelve and one-half seconds for glasscontainers weighing from 155 grams to 284 grams, respectively.

When the glass containers have been cooled sufficiently to set thestrain in them, the cooling tubes are raised and the cooling shrouds andcooling nozzles are lowered in a cooling tubes raised and coolingshrouds lowered step 93. Next, the thermally strengthened glasscontainers are lowered to an outgoing conveyer belt in a glasscontainers lowered to outgoing conveyer belt step 94. This completes thethermal strengthening cooling step 85, and the glass containers thenproceed to the glass containers further cooling step 86 which has beenpreviously mentioned.

Following the thermal strengthening process 75, the glass containers maybe provided to the cold end of the glass container manufacturing linefor application of the cold end process 77. If the glass containers areto be coated, they must be at a temperature of between approximately 100degrees Centigrade and 150 degrees centigrade. They may be coated, forexample, with a lubricious coating in a cold end coating step 95. Theglass containers are then transported to an inspection area in a glasscontainers moved to inspection area step 96, and they are inspected inan inspect glass containers step 97 (where they are typically at areduced temperature of between approximately 25 degrees Centigrade and80 degrees Centigrade). The thermally strengthened glass containers arethen complete, as indicated in a strengthened glass containers completetermination step 98.

Moving next to FIG. 4, several of the key components of thepost-manufacture glass container thermal strengthening process practicedby the present invention are illustrated in conjunction with a glasscontainer 100. The glass container 100 is supported throughout thepost-manufacture glass container thermal strengthening process by tongs102 that have removed the glass container 100 from a special temperingLehr (not shown) that has reheated the glass container 100. In FIG. 4,the glass container 100 is shown located directly above a cylindricalcooling shroud 104 and above a bottom cooling nozzle 110 that is locatedinside the cooling shroud 104 nearer the bottom than the top thereof. Acooling tube 106 having a tube nozzle 108 located at its distal end isshown with the tube nozzle 108 being located above the glass container100. More detailed descriptions of the cooling shroud 104, the bottomcooling nozzle 104, the cooling tube 106, and the tube nozzle 108 willbe provided below in conjunction with FIGS. 7 through 18.

Referring next to FIGS. 5 and 6, the post-manufacture glass containerthermal strengthening apparatus is shown with the glass container 100lowered entirely into the cooling shroud 104 so that the bottom of theglass container 100 is located above the bottom cooling nozzle 110 toprovide cooling air to cool the bottom of the glass container 100. Theorthogonal apertures 112 in the cooling shroud 104 direct the flow ofcooling air onto the neck and finish of the glass container 100, and theangled apertures 114 direct cooling air onto the lower portion of theneck, the shoulders, and the body of the glass container 100. Thecooling shroud 104 may optionally be rotated to “smear” the jets ofcooling air from the orthogonal apertures 112 and the angled apertures114, with the rotation either being continuous or oscillating.

The hole pattern in the cooling shroud 104, the size of the coolingshroud 104 (i.e., the inside diameter and the outside diameter), thenumber of the apertures 112 and 114, the diameters of the apertures 112and 114, the pressure setting, and whether the apertures 112 and 114 areradial and/or angled can all be modified to optimize the strength of theglass container 100 by tailoring the compression stress profile on theouter surface of the glass container 100. In this way, strength can bemaximized for whatever type of performance requirement that isdesired—be it burst, drop, vertical load, impact, or thermal shockresistance. Typical cooling air pressure provided to the cooling shroud104 may be approximately 75 mbar to approximately 150 mbar.

Cooling air is also supplied through the cooling tube 106 to the tubenozzle 108, which directs cooling air onto the inside surfaces of theglass container 100. The cooling tube 106 and the tube nozzle 108 may beoscillated between the position shown in FIG. 5 near the bottom of theneck of the glass container 100 (or optionally from a position higher upin the neck of the glass container 100) and the position shown in FIG. 6nearer the bottom of the glass container 100 (or optionally a higher orslightly lower position in the glass container 100). The cooling tube106 and the tube nozzle 108 may be oscillated between these twopositions up to approximately six times per glass container 100, or,optionally, only once to the position shown in FIG. 6. The speed of theoscillation may be constant, or it may vary during the stroke depth, andit may also optionally be paused briefly at any position.

The plunging of the cooling tube 106 inside the glass container 100 setsup beneficial air flow patterns. These flow patterns are enhanced by theengineered geometry of the tube nozzle 108 at the distal end of thecooling tube 106. The feed area (the inside diameter of the cooling tube106) and the exhaust area (the inside diameter of the finish of theglass container 100 minus the outside diameter of the cooling tube 106)must be carefully balanced to provide for maximum airflow into and outof the glass container 100. The size of the cooling tube 106 may thus bedetermined.

The position, speed, stroke, and pressure setting of the cooling tube106 can all be modified to optimize the strength of the glass container100 by tailoring the compression stress profile on the inner surface. Inthis way, strength can be maximized for whatever type of performancerequirement that is desired—be it burst, drop, vertical load, impact orthermal shock resistance, or adjusted to compensate for bottle geometryconsiderations (e.g., challenging shapes, wall thickness variations).Typical cooling air pressure provided to the tube nozzle 108 may beapproximately 2.7 bar±0.7 bar, and the stroke of the cooling tube 106and the tube nozzle 108 may be up to approximately 180 mm.

The design of the bottom cooling nozzle 110 may also be modified tofacilitate the optimization of the strength of the glass container 100.The bottom cooling nozzle 110 is positioned and to cool the outsidebottom of the glass container 100. Typical cooling air pressure providedto the bottom cooling nozzle 110 may be approximately 0.7 bar.

Referring now to FIGS. 7 through 12 in addition to FIGS. 4 through 6, itmay be seen that the cooling shroud 104 is open both on the top end andon the bottom end thereof, and has the pluralities of the orthogonalapertures 112 and the angled apertures 114 located in the side wallsthereof, each of which may be approximately 2 mm in diameter. Thecooling shroud 104 thus functions to cool the outside surfaces of theglass container 100, other than the bottom of the glass container 100.The outer side of the cooling shroud 104 will be supplied with airpressure in an annular cavity formed between the outer surface of thecooling shroud 104 and an enclosing member not shown in FIGS. 7 through12.

The cooling shroud 104 uses tiny hole patterns (for example,approximately 18 sets of each of the orthogonal apertures 112 and theangled apertures 114) in the side walls thereof to evenly cover theexterior surfaces of the glass container 100. It may be best seen inFIGS. 6 and 10 that the large plurality of angled apertures 114 in theside walls of the cooling shroud 104 are angled downwardly, for exampleat an angle of approximately 45 degrees. These angled apertures 114 willcool the shoulders and the side wall of the glass container 100. Locatedabove the angled apertures 114 are a large plurality of orthogonalapertures 112 that will cool the neck and outside of the finish of theglass container 100.

The air pressure in the angled apertures 114 and the orthogonalapertures 112 is preferably approximately 75 mbar to 300 mbar (30 to 120inches of water) as measured in each individual annulus. A large numberof tiny angled apertures 114 and the orthogonal apertures 112 are usedto evenly cover the exterior surfaces of the glass container 100. Inaddition, the cooling shroud 104 is rotationally oscillated, and may beaxially oscillated instead of or in addition to the rotation, to smoothout the cooling pattern on the glass container 100.

Referring now to FIGS. 13 through 15 in addition to FIGS. 4 and 5, itmay be seen that the tube nozzle 108 has an annular upper portion 120that fits within the interior of the end of the cooling tube 106, and anannular lower portion 122 that abuts the bottom of the cooling tube 106.Located below the annular lower portion 122 is an outwardly flaringfrustroconical segment 124 that may be at an angle of approximately 30degrees from vertical, and may be, for example, approximately 12 mm wideat its widest diameter. A centrally located aperture 126 that may be,for example, approximately 4 mm in diameter, extends through the annularupper portion 120, the annular lower portion 122, and the frustroconicalsegment 124. Eight radially spaced apart longitudinal apertures 128 thatmay be, for example, approximately 2.3 mm in diameter, extend throughthe annular upper portion 120 and the annular lower portion 122.

The cooling tube 106 typically has an approximately twelve millimeteroutside diameter and an approximately ten millimeter inside diameterwhen it will be used with a 330 milliliter single servingbeer-container-type finish, and may have an approximately 19.05millimeter outside diameter and an approximately 16.56 millimeter insidediameter when it will be used with a 500 milliliter glass container ofthe size typically used for ice tea or juice. Both the cooling tube 106and the nozzle 108 are easily and quickly replaceable while installed onthe post-manufacture glass container thermal strengthening equipment.The cooling tube 106 is mounted in a straight, vertical position, andmay be lowered into the interior of the glass container 100.

Air pressure is supplied through the cooling tube 106 to the nozzle 108,and exits the nozzle 108 through the centrally located aperture 126 andthe longitudinal apertures 128. The air pressure feeding the coolingtube 106 is preferably approximately 2.0 bar±0.7 bar (30 psi±10 psi).The cooling air exiting the nozzle 108 through the centrally locatedaperture 126 cools the inside of the glass container 100 at the bottom,while the cooling air exiting the nozzle 108 through longitudinalapertures 128 is dispersed and directed radially outwardly by thefrustroconical segment 124. By oscillating the cooling tube 106 up anddown, the entire length of the interior surfaces of the glass container100 may be cooled. In a preferred embodiment, the nozzle 108 can becycled up and down in an approximately 180 millimeter stroke for atypical long neck beer container. The cooling air supplied by thecooling tube 106 through the nozzle 108 exits the glass container 100through the finish of the glass container 100.

Referring now to FIGS. 16 through 18 in addition to FIGS. 4 through 6,it may be seen that the bottom cooling nozzle 110 is mounted in astationary position coaxially within the cooling shroud 104 near thebottom thereof. The position of the bottom cooling nozzle 110 isadjustable in height for accommodating different bottle sizes within thecooling shroud 104. The bottom cooling nozzle 110 is supplied withcooling air to a chamber 130 located in the bottom thereof by a duct notshown in these figures. The bottom cooling nozzle 110 has a centrallylocated aperture 132 oriented upwardly which is surrounded by sixradially spaced apart angled apertures 134 that may be, for example, atangles of approximately 30 degrees from vertical, with the top of thebottom cooling nozzle 110 being frustroconical and beveled at an angleof approximately 60 degrees from vertical. The centrally locatedaperture 132 and the angled apertures 134 may be, for example,approximately 3.2 mm in diameter.

Cooling air is supplied to the chamber 130 in the bottom cooling nozzle110, and then exits the bottom cooling nozzle 110 through the centrallylocated aperture 132 and the six radially spaced apart angled apertures134. The air pressure supplied to the bottom cooling nozzle 110 ispreferably approximately 0.34 bar to 0.69 bar (5 to 10 psi). The spraypattern of the centrally located aperture 132 and the six radiallyspaced apart angled apertures 134 covers the bottom surface of the glasscontainer 100. The cooling air supplied by the bottom cooling nozzle 110exits the cooling shroud 104 at the bottom of the cooling shroud 104. Itis essential that the design of the bottom cooling nozzle 110 is suchthat it will not serve as a catch point for broken glass that mightshatter during the cooling process, since such broken glass needs tohave a path to fall clearly out of the cooling shroud 104.

Preferably, the tongs 102 (shown in FIGS. 4 through 6) holding the glasscontainer 100 must hold it sufficiently rigidly to prevent it fromswinging while it is located in the cooling shroud 104. Alternatively,although they are not shown in the figures, it may be desirable to havea plurality of alignment pins located inside the cooling shroud 104 toprevent the glass container 100 from swinging. The alignment pins wouldbe made of a material capable of withstanding the high temperatureswhile not causing checks in the glass of the glass container 100. Theymust also be easily replaceable. Since there will be a scrubbing actionbetween the alignment pins and the glass container 100 due to therotation of the cooling shroud 102, the alignment pins should bedesigned with a gap.

Referring next to FIG. 19, the major components of the post-manufactureglass container thermal strengthening apparatus used by the presentinvention are illustrated. While the thermal strengthening apparatuslooks quite complex as shown in the drawings, it is relatively moresimple when thought of as an assembly consisting of eight subassemblies.Four of these subassemblies function to move the glass containers, oneof the subassemblies functions to cool the outside of the glasscontainers, one of the subassemblies functions to support a subassemblythat cools the interiors of the glass containers, and the lastsubassembly functions to cool the interiors of the glass containers.

The first subassembly that functions to move the glass containers is asupport member 140 located on the floor on which the post-manufactureglass container thermal strengthening apparatus is located that has twoupright drive covers 142 and 144 mounted extending upwardly nearopposite ends of a base member 146 and a operating mechanism cover 145located between the upright drive covers 142 and 144. The secondsubassembly that functions to move the glass containers is a tongs armsupport apparatus 148 that is mounted adjacent the upright drive cover142 and is supported by the base member 146 of the support member 140,and the third subassembly that functions to move the glass containers isa second tongs arm support apparatus 150 that is mounted adjacent theupright drive cover 144 and is supported by the base member 146 of thesupport member 140.

The tongs arm support apparatus 148 has a support post 152 that supportsa tongs drive arm 154 mounted at its proximal end at the top of thesupport post 152. Located at the distal end of the tongs drive arm 154is a tongs arm mounting member 156. Similarly, the tongs arm supportapparatus 150 has a support post 158 that supports a tongs drive arm 160mounted at its proximal end at the top of the support post 158. Locatedat the distal end of the tongs drive arm 160 is a tongs arm mountingmember 162.

The fourth subassembly that functions to move the glass containers is atongs support member 166 having a tongs bar 164 mounted at one end ontothe tongs arm mounting member 156 of the tongs drive arm 154 and at theother end onto the tongs arm mounting member 162 of the tongs drive arm160. Four sets of tongs operating apparatus 168 are supported by thetongs bar 164, with each set of the tongs operating apparatus 168supporting a pair of the tongs 102 only a portion of one of which pairsis visible in FIG. 19). The tongs arm support apparatuses 148 and 150function to drive the tongs support member 166 through an approximately180 degree arc that will pick up the glass containers 100 from aconveyor exiting a special tempering Lehr (not shown in FIG. 19) thatreheats the glass containers 100, to move the glass containers 100 to aposition in which the post-manufacture glass container thermalstrengthening method used by the present invention is performed, andfinally to move the glass containers 100 to a conveyor removing theglass containers 100 from the post-manufacture glass container thermalstrengthening apparatus.

The tongs arm support apparatus 148 and the tongs arm support apparatus150 are arranged and configured to operate together, maintaining thetongs bar 164 of the tongs support member 166 parallel to the basemember 146 of the support member 140 and a surface upon which thesupport member 140 is mounted. As the tongs arm support apparatuses 148and 150 drive the tongs support member 166, the tongs operatingapparatus 168, and the tongs 102 through the approximately 180 degreearc, the tongs 102 are all maintained in a vertical position such thatthe glass containers 100 carried by the tongs 102 will be maintaineddirectly below the tongs operating apparatus 168, irrespective of theangular position of the tongs arm support apparatuses 148 and 150 andthe tongs support member 166, the tongs operating apparatus 168, and thetongs 102.

The subassembly that functions to cool the outside of the glasscontainers is a cooling shroud mechanism 170 that is mounted on the basemember 146 of the support member 140 in a location intermediate theupright drive cover 142 and the upright drive cover 144. The coolingshroud mechanism 170 has two shroud mechanism subassemblies 172 and 174that are located side-by-side on the floor on which the post-manufactureglass container thermal strengthening apparatus is located and betweenthe tongs arm support apparatus 148 and 150, each of which has twocooling shrouds 104 contained therein (and two bottom cooling nozzles110 not shown in FIG. 19 contained therein). The cooling shroudmechanism 170 also contains apparatus for operating the cooling shrouds104 and the bottom cooling nozzles 110.

The shroud mechanism subassemblies 172 and 174 have two positions: afirst, retracted position in which they are lowered, which is theposition shown for the shroud mechanism subassembly 172 in FIG. 19, asecond, extended position in which they are raised, which is theposition shown for the shroud mechanism subassembly 174 in FIG. 19. Inthe lowered position, the tongs support member 166 and the tongs 102 canfreely move glass containers either into position for thermal tempering,or away from the cooling position after thermal tempering. In the raisedposition, glass containers supported by the tongs 102 on the tongssupport member 166 with the tongs arm support apparatus 148 and 150 inposition for thermal tempering will be contained within cooling shrouds104 and above bottom cooling nozzle 110 located in the shroud mechanismsubassemblies 172 and 174 for thermal tempering.

While the shroud mechanism subassembly 174 is shown in its upwardlyextended position and the shroud mechanism subassembly 172 is shown inits downwardly retracted position, it will be appreciated that inoperation the shroud mechanism subassemblies 172 and 174 will movetogether between their downwardly retracted and upwardly extendedpositions. Other aspects of the cooling shroud mechanism 170 will bediscussed below in conjunction with the discussion of FIGS. 31 through35.

The subassembly that functions to support a subassembly that cools theinteriors of the glass containers is a cooling tube support assembly 176that has two support arms 178 and 180, the bottom ends of which arerespectively mounted onto the support post 152 of the tongs arm supportapparatus 148 and the support post 158 of the tongs arm supportapparatus 150. The support arms 178 and 180 extend upwardly above thecooling shroud mechanism 170, and have a cooling tube assembly supportbridge 182 mounted at their respective top ends and extendingtherebetween above the cooling shroud mechanism 170. The cooling tubeassembly support bridge 182 and the support arms 178 and 180 are mountedin a fixed position and are arranged and configured to allow the tongsarm support apparatus 148 and 150 to drive the tongs support member 166through its approximately 180 degree arc.

Finally, the subassembly that functions to cool the interiors of theglass containers is a cooling tube assembly 184 that is mounted on thecooling tube assembly support bridge 182 above the shroud mechanismsubassemblies 172 and 174. The cooling tube assembly 184 supports fourof the cooling tubes 106 each having a tube nozzle 108 located at thebottom thereof. The cooling tube assembly 184 has a base plate 186 thatis mounted on the cooling tube assembly support bridge 182 of thecooling tube support assembly 176.

Two vertically extending support rails 188 and 190 extend upwardly fromthe respective ends of the base plate 186. A support plate 192 ismounted between the top ends of the support rails 188 and 190. Acrossbar 194 is slidably mounted on the support rails 188 and 190 and isdriven in a vertical direction between the support plate 192 and thebase plate 186 by a screw mechanism 196 that is operated by a motor 198.

Extending downwardly from the crossbar 194 at spaced-apart intervals arefour tube support sleeves 200 (only two of which are shown in FIG. 19)each of which support a cooling tube 106 (only two of which are shown inFIG. 19). The cooling tube assembly 184 is arranged and configured sothat the cooling tubes 106 are respectively above and coaxial with thecooling shrouds 104 located in the shroud mechanism subassemblies 172and 174 of the cooling shroud mechanism 170. Cooling air may be suppliedto the cooling tube assembly 184 so that it will be provided to each ofthe cooling tubes 106.

The cooling tube assembly 184 is operable to drive the cooling tubes 106between two positions: a first, raised position, and a second, loweredposition. In the raised position, the tongs support member 166 and thetongs 102 can freely move glass containers 100 either into position forthermal strengthening, or from the position for thermal tempering afterthermal tempering is complete, with the bottom ends of the cooling tubes106 and the nozzles 108 being located above the tongs support member 166and the tongs 102 when the cooling tube assembly 184 is in the raisedposition. In the lowered position, the bottom ends of the cooling tubes106 and the nozzles 108 will be respectively located deep within glasscontainers 100 that are supported by the tongs support member 166 andthe tongs 102 for thermal tempering.

Referring next to FIG. 20, the post-manufacture glass container thermalstrengthening apparatus used by the present invention is shown with asource of reheated glass containers 100 and with the apparatus ontowhich the thermally strengthened glass containers 100 exit thepost-manufacture glass container thermal strengthening apparatus. Thepost-manufacture glass container thermal strengthening apparatus willmove the glass containers 100 between three positions: a first positionin which they will be picked up from a supply conveyor 210 after theyhave been reheated, a second position at which the glass containers 100will be thermally cooled, and a third position at which the glasscontainers 100 will be deposited on a deadplate 212. While in theexemplary embodiment illustrated herein the tongs support member 166 hasfour sets of tongs 102 mounted therefrom, each of which tongs 102 may beused to pick up and move a single glass container 100, it will beappreciated that any number of sets of tongs 102 may instead be used.

The supply conveyor 210 provides the reheated glass containers 100 tothe post-manufacture glass container thermal strengthening apparatus,and the tongs 102 of the tongs drive arm 154 picks up the glasscontainers 100 and moves them in an arc by the rotation of the tongs armsupport apparatus 148 and 150 (the latter of which is not shown in FIG.20). The reheated glass containers 100 are moved in a counterclockwisearc approximately 90 degrees to a position in which they are thermallystrengthened.

The thermally strengthened glass containers 100 continue to be movedcounterclockwise in an arc by the rotation of the tongs arm supportapparatus 148 and 150 for an additional approximately 90 degrees, atwhich point the thermally strengthened glass containers 100 aredeposited by the tongs 102 on the deadplate 212. After the tongs 102 areraised, the thermally strengthened glass containers 100 are pushed ontoan exit conveyor 214 by a pusher mechanism 216. The thermallystrengthened glass containers 100 may then be conveyed away from thepost-manufacture glass container thermal strengthening apparatus, andmay optionally be further cooled by fans or a subsequent cooling unit(not shown in FIG. 20).

Referring now to FIGS. 21 through 28, a complete sequence of thepost-manufacture glass container thermal strengthening method isillustrated. These figures are all shown as cross-sections along thecenterline of the post-manufacture glass container thermal strengtheningapparatus. In FIG. 21, the reheated glass containers 100 are shownexiting a special tempering Lehr 220 adjacent to the post-manufactureglass container thermal strengthening apparatus on the supply conveyor210. The special tempering Lehr 220 is preferably located immediatelydownstream of the I.S. Machine (not shown in FIGS. 21 through 28) asclosely as possible to minimize cooling of the glass container 100before they enter the special tempering Lehr 220. The tongs supportmember 166 is being rotated clockwise in an arc with the tongs 102 shownjust above a reheated glass container 100. It will continue to rotateclockwise until the tongs drive arm 160 is approximately horizontal, atwhich time the tongs 102 will grasp the finish of a reheated glasscontainer 100, the position of the tongs 102 at that time beingillustrated in phantom lines.

Following the tongs 102 grasping the finish of a reheated glasscontainer 100, the tongs support member 166 will begin to be rotatedcounterclockwise in an arc with the tongs 102 lifting the reheated glasscontainer 100 off of the supply conveyor 210 in a counterclockwise arcas shown in FIG. 22. The tongs support member 166 will continue torotate counterclockwise in an arc with the tongs 102 until the tongssupport member 166 is vertical, in which position the reheated glasscontainer 100 is located above the cooling shroud 104 and below thecooling tube 106 and the tube nozzle 108, as shown in FIG. 23.

As shown in FIG. 24, the cooling shroud 104 will be raised by the shroudmechanism subassembly 174 of the cooling shroud mechanism 170 tosurround the reheated glass container 100, with the bottom coolingnozzle 110 located just below the bottom of the reheated glass container100, and the cooling tube 106 and the tube nozzle 108 will be lowered bythe cooling tube assembly 184 until the tube nozzle 108 is in the neckof the reheated glass container 100. At this point, cooling air will beprovided by one or more cooling air sources to the cooling shroud 104,to the cooling tube 106 and the tube nozzle 108, and to the bottomcooling nozzle 110.

The cooling shroud 104 optionally is rotated and/or oscillated up anddown slightly to smear cooling air coming in from the orthogonalapertures 112 and the angled apertures 114 (both of which are shown inFIGS. 5 and 6) onto the outer surfaces of the reheated glass container100 to cool them. Simultaneously, the bottom cooling nozzle 110 willdirect cooling air onto the bottom of the reheated glass container 100to cool it. Also simultaneously, the cooling tube 106 and the tubenozzle 108 will be oscillated between the higher position shown in FIG.24 and a lower position shown in FIG. 25 to cool the inner surfaces ofthe reheated glass container 100. As mentioned previously, the coolingtube 106 and the tube nozzle 108 may be oscillated between one andapproximately six times.

At this point, the glass container 100 surfaces are cooled quickly anduniformly, setting up a temperature profile through the glass whichresults in a permanent stress profile once all of the glass is cooledbelow the Strain Point, preferably to a range of between approximately400 degrees Centigrade and approximately 450 degrees Centigrade. Sinceall areas of the glass containers 100 are cooled below the Strain Point,including the middle of the thicker areas that typically take longer tocool, the stress profile throughout the glass containers 100 will becloser to an ideal theoretical stress distribution throughout the wallsof the glass container 100, varying from compression at the outer wallof a glass container to tension in the interior of the wall of the glasscontainer to compression at the inside wall of the glass container. Thisresults in the glass containers 100 being stronger, and also makespossible the manufacture of thinner walled and lighter glass containersthat still have excellent strength characteristics.

Following the performance of the post-manufacture glass containerthermal strengthening method as shown in FIGS. 24 and 26, the coolingshroud 104 and the bottom cooling nozzle 110 will be lowered by theshroud mechanism subassembly 174 of the cooling shroud mechanism 170 topositions below the thermally strengthened glass container 100, and thecooling tube 106 and the tube nozzle 108 will be raised by the coolingtube assembly 184 until the tube nozzle 108 is above the neck of thethermally strengthened glass container 100, as shown in FIG. 26.

The tongs support member 166 will then be rotated counterclockwise in anarc with the tongs 102 delivering the thermally strengthened glasscontainer 100 where its bottom is resting on the deadplate 212, as shownin FIG. 27. At this point, the tongs drive arm 160 is approximatelyhorizontal, and the tongs 102 will release the finish of the thermallystrengthened glass container 100 and begin to rotate clockwise, leavingthe thermally strengthened glass container 100 on the deadplate 212. Asthe tongs drive arm 160 continues to rotate clockwise, the pushermechanism 216 will push the thermally strengthened glass container 100onto the exit conveyor 214, as shown in FIG. 28.

Referring next to FIG. 29, the installation of the tongs arm supportapparatus 148 and 150 onto the support member 140 and the installationof the tongs support member 166 onto the tongs drive arms 154 and 160are illustrated. The support member 140 is shown with both the operatingmechanism cover 145 and the upright drive covers 142 and 144 (all ofwhich are shown in FIG. 19) removed for clarity. The support post 152 ofthe tongs arm support apparatus 148 is mounted onto the base member 146at end thereof, and the support post 158 of the tongs arm supportapparatus 150 is mounted onto the base member 146 at the other endthereof. The tongs drive arm 154 of the tongs arm support apparatus 148is supported for rotation at the top end of the support post 152, andthe tongs drive arm 160 of the tongs arm support apparatus 150 issupported at the top end of the support post 158.

A drive motor 230 is mounted on the base member 146 of the supportmember 140 at the center thereof, and operates to rotate a drive shaft232 having toothed pulleys 234 and 236 mounted on the respective endsthereof and supported for rotation by four bearing support members 238.The toothed pulley 234 drives a toothed pulley 240 that rotates thetongs drive arm 154 through a toothed belt 242. The toothed pulley 236drives a toothed pulley 244 that rotates the tongs drive arm 160 througha toothed belt 246. Located on and moving with the tongs drive arm 154is a tongs support rotation member indicated generally by the referencenumeral 248, and located on and moving with the tongs drive arm 160 is atongs support rotation member indicated generally by the referencenumeral 250.

The tongs support rotation member 248 and 250 operate to maintain thetongs support member 166 in its vertical orientation as the tongs drivearms 154 and 160 drive the tongs support member 166 through the arc asdescribed in conjunction with FIGS. 21 through 28. Mounted on the outerside of the support post 152 of the tongs arm support apparatus 148 is asupport bracket 252, and mounted on the outer side of the support post158 of the tongs arm support apparatus 150 is a support bracket 254. Thesupport brackets 252 and 254 will support the cooling tube supportassembly 176 and the cooling tube assembly 184 (both of which are shownin FIG. 19).

Referring next to FIG. 30, the crossbar 194 is mounted onto the supportrail 188 and 190 for vertical movement between the support plate 192 andthe base plate 186. The crossbar 194 is driven by the motor 198, whichdrives the screw mechanism 196 that extends through a threaded aperture260 in the crossbar 194. Two of the tube support sleeves 200 are mountedon a tube support plate 262, and the other two tube support sleeves 200are mounted on a tube support plate 264. The two tube support plates 262and 264 are in turn mounted onto the crossbar 194.

Referring next to FIG. 31, portions of the shroud mechanism subassembly172 and the shroud mechanism subassembly 174 are shown, again with theshroud mechanism subassembly 172 in its lowered or inactive position andthe shroud mechanism subassembly 174 in its raised or cooling position(although in operation typically both the shroud mechanism subassemblies172 and 174 would operate together in the same positions). It may beseen that each of the shroud mechanism subassemblies 172 and 174 have apair of cooling shrouds 104 respectively mounted in shroud housings 270and 272. The shroud housings 270 and 272 are respectively raised andlowered with electromechanically actuator mechanisms 274 and 276 (whichare each typically a servo-driven screw mechanism) mounted on theoperating mechanism cover 145 of the support member 140 (both of whichare shown in FIG. 19) on which the post-manufacture glass containerthermal strengthening apparatus is located.

Referring now to FIG. 32, a portion of the shroud mechanism subassembly174 is cut away to show some of the mechanisms contained therein.Specifically, a telescopic shroud air supply tube 280 and a telescopicbase air supply tube 282 are shown that respectively supply cooling airto the cooling shroud 104 and the bottom cooling nozzle 110. Thus, asthe shroud mechanism subassembly 174 is raised and lowered, the supplytubes 280 and 282 will extend and contract. The shroud air supply tube280 leads to a passageway 284 supplying cooling air to a shroud coolingcavity 286 located intermediate the shroud housing 272 and both of thecooling shrouds 104 located in the shroud housing 272.

Preferably, the cooling shrouds 104 are installed in the shroud housing272 such that the shroud cooling cavity 286 is sealed at the top andbottom of the cooling shrouds 104 so that all cooling air suppliedthrough the shroud air supply tube 280 will be delivered through theorthogonal apertures 112 and the angled apertures 114 in the coolingshroud 104 (which are best shown in FIGS. 5 and 6). The cooling shroud104 is optionally rotated during the cooling operation, as will becomeevident below in conjunction with a discussion of FIG. 35. (If desired,the cooling shrouds 104 may optionally be mounted for axial rotation inthe shroud housing 160 as well.)

The base air supply tube 282 leads to a nozzle supply tube 288 thatrigidly supports the bottom cooling nozzle 110 in position within thecooling shroud 104. Cooling air delivered through the base air supplytube 282 will be delivered to the centrally located aperture 132 and theangled apertures 134 in the bottom cooling nozzle 110 (shown in FIGS. 16through 18).

Referring next to FIGS. 33 and 34, additional detail of the shroudmechanism subassembly 172 is illustrated. The location of a shroudrotation mechanism is indicated with the reference numeral 290. Also,the location of a cullet chute 292 below the cooling shrouds 104 in theshroud housing 270 is indicated. It should be noted that since thecooling shrouds 104 are open at the bottom (as well as at the top), andsince the nozzle supply tubes 288 and the bottom cooling nozzles 110 aresized and placed so as to leave the opening at the bottom of the coolingshrouds 104 largely unobstructed, should glass containers 100 breakwhile inside the cooling shrouds 104, the broken glass may freely fallout of the cooling shrouds 104 and into the cullet chute 292, from whichis may be directed to a collection area (not shown in FIG. 33 or 34).

Referring now to FIG. 35, additional hardware for use in an embodimentin which the cooling shrouds 104 are rotated during the coolingoperation is shown. Upper and lower bearings 300 and 302, respectively,are used to rotatably support the cooling shrouds 104 in the shroudhousing 270. Located below the upper bearing 300 is an upper sealingmember 304, and located above the lower bearing 302 is a lower sealingmember 306. If desired, the shroud air supply tube 280 (shown in FIG.32) can also provide cooling air through an additional passageway 308(in addition to the passageway 284 shown in FIG. 32). A mounting surface310 is shown in the side of the shroud housing 160. Finally, a locatingpin 312 for rotation of the cooling shroud 104 is shown near the bottomthereof. The motor and the linkage driving 312 are not shown in FIG. 35.

Referring next to FIGS. 36 through 38, an exemplary manufacturing linefor the post-manufacture glass container thermal strengthening processpracticed by the present invention that is located downstream of the hotend (the I.S. machines molding the glass containers, not illustratedherein) and upstream of the cold end (the coating and inspectionmachines, not illustrated herein) is illustrated. The special temperingLehr 220 has the supply conveyor 210 running therethrough. Glasscontainers 100 formed in an I.S. machine (not shown) are placed onto thesupply conveyor 210 at the right side of the special tempering Lehr 220as illustrated in FIG. 36 after having been discharged from the I.S.machine. As the glass containers 100 enter the special tempering Lehr220, they are typically between approximately 500 degrees Centigrade andapproximately 600 degrees Centigrade.

The special tempering Lehr 220 is typically set at temperatures rangingfrom approximately 600 degrees Centigrade at the entrance zone (on theright side as illustrated in FIG. 36) to approximately 715 degreesCentigrade at the exit zone (on the right side as illustrated in FIG.37). A typical size for the special tempering Lehr 220 is approximatelysixteen feet (4.9 meters) long. The special tempering Lehr 220 may have,for example, four independent temperature controlled zones. The glasscontainers 100 will typically spend between two and one-half to threeand one-half minutes in the special tempering Lehr 220, and will beheated to a temperature of approximately 620 degrees Centigrade toapproximately 680 degrees Centigrade in the special tempering Lehr 220.This range is significant since if the glass containers are below 620degrees Centigrade it is not possible to obtain adequate compressivestresses in the post-manufacture glass container thermal strengtheningprocess practiced by the present invention, and if the glass containersare above approximately 680 degrees Centigrade deformations may occur inthem.

Following the performance of the post-manufacture glass containerthermal strengthening process, the thermally strengthened glasscontainers 100 are deposited on the deadplate 212. The thermallystrengthened glass containers 100 are then pushed by the pushermechanism 216 onto the exit conveyor 214, which takes them away from thepost-manufacture glass container thermal strengthening apparatus. Sincethe thermally strengthened glass containers 100 are still quite hot(although they are uniformly well below the Strain Point 70), they maybe subjected to cooling air from a schematically illustrated fan array320 for cooling them more completely before they reach the cold endequipment (not shown herein). Also shown in FIGS. 37 and 38 is thecullet chute 292 for collecting broken glass falling out of thepost-manufacture glass container thermal strengthening apparatus, whichbroken glass is collected in a collection bin 322.

Referring next to FIGS. 39 through 41, an alternate embodiment bottomcooler 340 for mounting in the bottom of the cooling shroud 104 as shownin FIG. 42 is illustrated. Instead of using the bottom cooling nozzle110 best shown in FIGS. 5 and 6 which is centrally located directlyunder the bottom of the glass container 100, the bottom cooler 340 maybe advantageous in that is offers excellent bottom coolingcharacteristics while presenting less of an obstruction to pieces of aglass container 100 that may break during the performance of thepost-manufacture glass container thermal strengthening method describedherein due to defects. Those skilled in the art will realize that if apiece of broken glass hangs up on the bottom cooling nozzle 110, theapparatus may have to be stopped to manually remove the broken glass.

The bottom cooler 340 instead is of a design which is entirely locatedclose to the inner wall of the cooling shroud 104 near the bottomthereof, and as such is entirely open under the bottom of a glasscontainer 100 that is being thermally strengthened. The bottom cooler340 includes a hollow cylindrical outer adjustable sleeve 342, a hollowcylindrical inner sleeve 344, and an annular locking element 346. Theupper portion of the outside of the inner sleeve 344 is curved inwardlyat the top thereof in a cross-sectionally arcuate manner as indicated bythe reference numeral 348. The bottom portion of the inner sleeve 344 isthreaded on the outer surface thereof.

The upper portion of the inside of the outer adjustable sleeve 342 iscurved inwardly at the top thereof in a cross-sectionally arcuate manneras indicated by the reference numeral 350. The inside of the outeradjustable sleeve 342 has an annular recess 352 located thereinimmediately below the inwardly curved portion 350. The outer adjustablesleeve 342 also has an inlet 354 leading from the outer surface of theouter adjustable sleeve 342 to the interior of the annular recess 352.The bottom portion of the outer adjustable sleeve 342 is threaded on theinner surface thereof a short distance below the annular recess 352.

The outer adjustable sleeve 342 is screwed onto the inner sleeve 344 sothat the inwardly curved portion 350 in the outer adjustable sleeve 342and the inwardly curved portion 348 in the inner sleeve 344 define a gap356 therebetween which will be the air outlet from the bottom cooler.The size of the gap 356 may be adjusted by rotating the outer adjustablesleeve 342 with respect to the inner sleeve 344. Once the gap 356 hasbeen adjusted as desired, the annular locking element 346 is screwedonto the threads on the outside of the inner sleeve 344 until it engagesand locks further rotation of the outer adjustable sleeve 342 on thetoothed pulley 244.

Referring now to FIG. 42, the bottom cooler is shown installed into asleeve 360 located inside the bottom portion of the cooling shroud 104.It may be seen that the sleeve 360 has a passageway 362 located in thebottom portion thereof that communicates between the inlet 354 in theouter adjustable sleeve 342 and an air supply tube 364 extending fromthe bottom of the sleeve 360. Thus, cooling air is supplied from the airsupply tube 364 to the bottom cooler, from which it is directed throughthe gap 356 between the inwardly curved portion 350 of the outeradjustable sleeve 342 and the inwardly curved portion 348 of the innersleeve 344 at a high velocity onto the bottom of the glass container100.

The bottom cooler shown in FIGS. 39 through 42 uses the Coanda effect,which causes the entrainment of ambient air around a fluid jet. Thus,the fluid jet emitted from the gap 356 between the inwardly curvedportion 350 of the outer adjustable sleeve 342 and the inwardly curvedportion 348 of the inner sleeve 344 will entrain ambient air locatednear the inner diameter of the inner sleeve 344 near the top thereof tothereby increase the amount of air that is directed onto the bottom ofthe glass container 100, thereby increasing the efficiency of thecooling of the bottom of the glass container 100.

Referring finally to FIGS. 43 and 44, an alternate embodimentpost-manufacture glass container thermal strengthening apparatus andrelated method are schematically illustrated. Rather than using anapparatus that removes the reheated glass containers 100 from a supplyconveyor, thermally strengthens the glass containers 100, and thendeposits the thermally strengthened glass containers 100 onto an exitconveyor, the method schematically illustrated in FIGS. 43 and 44maintains the glass containers 100 on an air-porous conveyor 370throughout the thermal strengthening process.

Instead, the cooling shrouds 104 and the cooling tube 106 and the tubenozzle 108 are lowered onto the reheated glass containers 100, until thebottoms of the cooling shrouds 104 are just above the upper surface ofthe porous conveyor 370. Bottom cooling elements 372 are located belowthe porous conveyor 370 and the cooling shrouds 104, and direct coolingair upwardly onto the bottoms of the reheated glass containers 100.Simultaneously, cooling air is supplied to the sides of the reheatedglass containers 100 along their entire height to cool their outsidesurfaces, and the cooling tube 106 and the tube nozzle 108 are loweredinto the interior of the reheated glass containers 100 to cool theirinteriors. The cooling tube 106 and the tube nozzle 108 may beoscillated as described above.

Two different methods are contemplated by this alternate embodiment. Inone embodiment, the bottom cooling elements 372 is stopped while thethermal strengthening process is performed, after which the bottomcooling elements 372 is moved to advance the next set of reheated glasscontainers 100 to be thermally strengthened. In the other embodiment,the post-manufacture glass container thermal strengthening apparatusmoved together with the bottom cooling elements 372, in which case theremust be a sufficient longitudinal number of thermally strengthening setsto allow the bottom cooling elements 372 to continue without stopping.

It may therefore be appreciated from the above detailed description ofthe exemplary embodiments practiced by the present invention that itteaches a post-manufacture glass container thermal strengthening processperformed while the glass containers are on a conveyor that results inan increase in the strength of the glass containers manufacturedaccording to the improved process. This increase in the strength ofglass containers is obtainable by the post-manufacture glass containerthermal strengthening process practiced by the present invention forglass containers of any design geometry. The post-manufacture glasscontainer thermal strengthening process enables the manufacture oflighter weight glass containers that have at least the same strength asconventional non-light weight glass containers.

The post-manufacture glass container thermal strengthening processpracticed by the present invention is fully adaptable to most if not allexisting glass container manufacturing lines. Further, thepost-manufacture glass container thermal strengthening process does notrequire either a replacement or a reconfiguration of existing I.S.machines at the hot end of glass container manufacturing lines. Thepost-manufacture glass container thermal strengthening processstrengthens glass containers without requiring the use of chemicalstrengthening methods to alter their hardness characteristics.

The apparatus used in the post-manufacture glass container thermalstrengthening process practiced by the present invention is of aconstruction which is both durable and long lasting, and which willrequire little or no maintenance to be provided by the user throughoutits operating lifetime. The advantages provided by the post-manufactureglass container thermal strengthening process practiced by the presentinvention substantially enhance its market appeal and thereby afford itthe broadest possible market. Finally, all of the aforesaid advantagesand objectives of the post-manufacture glass container thermalstrengthening process practiced by the present invention are achievedwithout incurring any substantial relative disadvantage.

Although the foregoing description of the post-manufacture glasscontainer thermal strengthening process practiced by the presentinvention has been shown and described with reference to particularembodiments and applications thereof, it has been presented for purposesof illustration and description is not intended to be exhaustive or tolimit the invention to the particular embodiments and applicationsdisclosed. It will be apparent to those having ordinary skill in the artthat a number of changes, modifications, variations, or alterations tothe invention as described herein may be made, none of which depart fromthe spirit or scope of the present invention. The particular embodimentsand applications were chosen and described to provide the bestillustration of the principles of the invention and its practicalapplication to thereby enable one of ordinary skill in the art toutilize the invention in various embodiments and with variousmodifications as are suited to the particular use contemplated. All suchchanges, modifications, variations, and alterations should therefore beseen as being within the scope of the present invention as determined bythe appended claims when interpreted in accordance with the breadth towhich they are fairly, legally, and equitably entitled.

1. A method of thermally strengthening glass containers on a conveyorbelt subsequent to the completed forming of the glass containers in thehot end of a glass container manufacturing line, the method comprising:following the completion of the glass container molding process,reheating the glass containers to increase their temperature to atemperature that is sufficiently high to obtain adequate compressivestresses in the glass containers but not so high that the glasscontainers may become deformed; and while the glass containers arelocated on the conveyor belt, simultaneously cooling the outer and innersurfaces of the glass containers rapidly so that all of the stresses inthe glass containers are locked in.
 2. A method as defined in claim 1,wherein the cooling step comprises: cooling the outer sides of eachglass container by directing a plurality jets of cooling air onto theouter sides of the glass container about its entire circumference;cooling the interior of the glass container by inserting a cooling tubehaving a tube nozzle at the distal end thereof into the interior of theglass container which delivers cooling air into the interior of theglass container and oscillating the cooling tube and the tube nozzlebetween one and six times; and cooling the bottom of the glass containerby directing cooling air through the conveyor belt onto the bottom ofthe glass container; wherein the cooling of the outer sides of the glasscontainer, the cooling of the interior of the glass container, and thecooling of the bottom of the glass container are all performedsimultaneously.
 3. A method as defined in claim 2, wherein the coolingthe outer sides step comprises: lowering a cylindrical cooling shroudfrom a first position above the glass container on the conveyor to asecond position surrounding the glass container on the conveyor in whicha bottom of the cooling shroud is located just above the conveyor belt;and directing cooling air from first and second pluralities of apertureslocated in the cooling shroud onto the outer sides of the glasscontainer on the conveyor belt.
 4. A method as defined in claim 3,wherein the first plurality of apertures in the cooling shroud arearranged and configured orthogonally in the cylindrical shroud body todirect cooling air radially inwardly onto the outside of the neck andfinish of the glass container on the conveyor belt.
 5. A method asdefined in claim 3, wherein the second plurality of apertures in thecooling shroud are arranged and configured angularly downwardly in thecylindrical shroud body to direct cooling air inwardly and downwardlyonto the outside of the body of the glass container on the conveyorbelt.
 6. A method as defined in claim 3, additionally comprising: acylindrical shroud support member that the cylindrical shroud is mountedupon; and a cylindrical shroud drive element for raising and loweringthe cylindrical shroud support member to move the cylindrical shroudbetween the first position the at least one second position when thedrive element is activated to operate the cylindrical shroud driveelement.
 7. A method as defined in claim 2, wherein the cooling theouter sides step comprises: lowering a cooling tube having a tube nozzlelocated at the bottom end thereof from a first position above the glasscontainer on the conveyor to a second position in which the cooling tubeand the tube nozzle are at least partially inserted into the glasscontainer located on the conveyor belt; and delivering cooling airprovided to the cooling tube through the tube nozzle into the interiorof the glass container on the conveyor belt.
 8. A method as defined inclaim 7, wherein the tube nozzle is located in the neck of the glasscontainer on the conveyor belt when the cooling tube and the tube nozzleare in the second position, and wherein the cooling tube and the tubenozzle are lowered to a third position in which the tube nozzle islocated nearer the bottom of the glass container in the cooling station.9. A method as defined in claim 8, further comprising: oscillating thecooling tube and the cooling tube nozzle between the second position andthe third position between one and six times.
 10. A method as defined inclaim 7, additionally comprising: a cooling tube support member that thecooling tube is mounted upon; and a cooling tube drive element forraising and lowering the cooling tube support member to move the coolingtube and the tube nozzle between the first position and the at least onesecond position when the drive element is activated to operate thecooling tube drive element.
 11. A method as defined in claim 2, whereinthe cooling the bottom of the glass container step comprises: providinga conveyor belt that is sufficiently permeable to cooling air to allowthe bottom of the glass container on the conveyor belt to be cooledsufficiently rapidly; and providing a bottom cooling element thatdirects cooling air upwardly through the cooling air permeable conveyorbelt onto the bottom of the glass container.
 12. A method as defined inclaim 11, wherein the bottom cooling element comprises: a high pressurefan.
 13. A method as defined in claim 1, additionally comprising:following the completion of the cooling step, further cooling the glasscontainers a temperature of approximately 100 degrees Centigrade toapproximately 150 degrees Centigrade.
 14. A method as defined in claim1, wherein the temperature to which the glass containers are reheated inthe reheating step is a temperature that is less than the SofteningPoint of the glass from which the glass containers are formed.
 15. Amethod as defined in claim 1, wherein the temperature to which the glasscontainers are reheated in the reheating step is between approximately620 degrees Centigrade and approximately 680 degrees Centigrade.
 16. Amethod as defined in claim 1, wherein the temperature to which the glasscontainers are cooled in the cooling step is a temperature that is belowthe Strain Point of the glass from which the glass containers areformed.
 17. A method as defined in claim 1, wherein the temperature towhich the glass containers are cooled in the cooling step is betweenapproximately 450 degrees Centigrade and approximately 400 degreesCentigrade.
 18. A method as defined in claim 1, wherein the glasscontainers are cooled in the cooling step so that all of the stresses inthe glass containers are locked in in less than approximately fifteen toapproximately twenty seconds.
 19. A method of thermally strengtheningglass containers manufactured in an I.S. machine in a glass containermanufacturing line at a location intermediate the hot end in which theglass containers are molded and the cold end in which the glasscontainers are inspected and on a conveyor belt, the method comprising:following the completion of the glass container molding process and theglass containers being discharged from the I.S. machine, reheating theglass containers in a special tempering Lehr located immediatelydownstream of the I.S. Machine as closely as possible to minimizecooling of the glass containers before they enter the special temperingLehr to increase their temperature to a temperature that is sufficientlyhigh to obtain adequate compressive stresses in the glass containers butless than the Softening Point of the glass from which the glasscontainers are formed and not so high that the glass containers maybecome deformed; and while the glass containers are located on theconveyor belt, simultaneously cooling the outer and inner surfaces ofthe glass containers rapidly to a temperature that is below the StrainPoint of the glass from which the glass containers are formed so thatall of the stresses in the glass containers are locked in in less thanapproximately fifteen to approximately twenty seconds.
 20. A method ofthermally strengthening formed glass containers on a conveyor belt,comprising: reheating the glass containers to increase their temperatureto a temperature that is sufficiently high to obtain adequatecompressive stresses in the glass containers; and while the glasscontainers are located on the conveyor belt, simultaneously cooling theouter and inner surfaces of the glass containers rapidly to lock in allof the stresses therein.